Asymptotic Wake Behavior of Swept, Blunt Trailing-Edge Airfoils

1994 ◽  
Vol 116 (1) ◽  
pp. 171-174
Author(s):  
G. V. Selby ◽  
F. H. Miandoab
Keyword(s):  
Streamwise Velocity ◽  
Vortex Generators ◽  
Wake Flow ◽  
Sweep Angle ◽  
Passive Flow Control ◽  
Blunt Trailing Edge ◽  
Passive Flow ◽  
Asymptotic Values ◽  
Flow Control Devices ◽  
Control Devices

The effect of base sweep and the addition of passive flow-control devices at constant base sweep angle (30 deg) on the asymptotic behavior of turbulent wakes produced by flatplate airfoils was experimentally examined. It was determined that values of the nondimensional streamwise velocity defect and wake thickness parameters for the grooved model with 30 deg swept base at fourteen base thicknesses downstream of the base at mid-span were closer to asymptotic values from empirical plane wake predictions than values for the 0, 30, and 45 deg swept baseline models and the 30 deg swept model with Wishbone vortex generators. The grooves apparently inhibited the three-dimensionality of the resulting wake flow.

Experimental Analysis on a Model of a Small Ducted Wind Turbine Equipped with Passive Flow Control Devices

2021 ◽  
Author(s):  
Elena-Alexandra Chiulan ◽  
Costin Ioan Cosoiu ◽  
Andrei-Mugur Georgescu ◽  
Anton Anton ◽  
Mircea Degeratu
Keyword(s):  
Flow Control ◽  
Wind Turbine ◽  
Experimental Analysis ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Control Devices

scholarly journals Fundamental Studies of Vortices Induced by a Vortex-Generator for Automotive Applications

2014 ◽  
Vol 553 ◽  
pp. 211-216
Author(s):  
Asiful Islam ◽  
Graham Doig
Keyword(s):  
Turbulence Models ◽  
Vortex Generator ◽  
Automotive Applications ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Simple Geometry ◽  
Image Velocimetry ◽  
Control Devices ◽  
Spatial Trajectory

For automotive applications, passive flow control devices can be used to reduce, delay or prevent flow separation. This study explores the nature of vortex generation and behaviour, numerically and experimentally, for a simple geometry at a Reynolds Number (Rex) of 5×105 and 1.945×106. The setup comprised a triangular vane vortex-generator mounted on a shallow ramp referenced from literature. Flow over the isolated ramp was validated with past experimental particle-image-velocimetry (PIV) data, which also highlighted the relative performance of various turbulence models. A parametric study was undertaken with the vane orientation defined by an angle-of-attack (β) and stream-wise location (xedge/xVG). These results revealed relationships between geometric parameters of the vortex generator, as well as the influence of the boundary layer thickness (hVG/δ), on the spatial trajectory of induced vortices.

Further Investigation of Vertical Stabilizer with Passive Flow Control Devices

2020 ◽  
Author(s):  
Yasushi Ito ◽  
Shunsuke Koike ◽  
Mitsuhiro Murayama ◽  
Yoshiyasu Ichikawa ◽  
Kazuyuki Nakakita ◽  
...  
Keyword(s):  
Flow Control ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Control Devices

Influence of Passive Flow-Control Devices on the Pressure Fluctuations at Wing-Body Junction Flows

2007 ◽  
Vol 129 (8) ◽  
pp. 1030-1037 ◽  
Author(s):  
Semih M. Ölçmen ◽  
Roger L. Simpson
Keyword(s):  
Flow Control ◽  
High Surface ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Wall Pressure Fluctuations ◽  
Flow Control Devices ◽  
Zero Degree ◽  
Control Devices

The effectiveness of passive flow-control devices in eliminating high surface rms pressure fluctuations at the junction of several idealized wing/body junction flows was studied. Wall-pressure fluctuation measurements were made using microphones along the line of symmetry at the wing/body junction of six different wing shapes. The wings were mounted on the wind tunnel floor at a zero degree angle-of-attack. The six wing shapes tested were: a 3:2 semi-elliptical-nosed NACA 0020 tailed generic body shape (Rood wing), a parallel center-body model, a tear-drop model, a Sandia 1850 model, and NACA 0015 and NACA 0012 airfoil shapes. Eight different fence configurations were tested with the Rood wing. The two double-fence configurations were found to be the most effective in reducing the pressure fluctuations. Two of the single fence types were nearly as effective and were simpler to manufacture and test. For this reason one of these single fence types was selected for testing with all of the other wing models. The best fence flow-control devices were found to reduce rms wall-pressure fluctuations by at least 61% relative to the baseline cases.

scholarly journals Five Megawatt Wind Turbine Power Output Improvements by Passive Flow Control Devices

Energies ◽  
2017 ◽  
Vol 10 (6) ◽  
pp. 742 ◽  
Author(s):  
Unai Fernandez-Gamiz ◽  
Ekaitz Zulueta ◽  
Ana Boyano ◽  
Igor Ansoategui ◽  
Irantzu Uriarte
Keyword(s):  
Flow Control ◽  
Wind Turbine ◽  
Power Output ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Control Devices

scholarly journals Computational Modeling of Gurney Flaps and Microtabs by POD Method

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2091 ◽  
Author(s):  
Unai Fernandez-Gamiz ◽  
Macarena Gomez-Mármol ◽  
Tomas Chacón-Rebollo
Keyword(s):  
Flow Control ◽  
Computational Cost ◽  
Aerodynamic Performance ◽  
Design Parameters ◽  
Cfd Simulations ◽  
Passive Flow Control ◽  
Gurney Flaps ◽  
Passive Flow ◽  
Flow Control Devices ◽  
Control Devices

Gurney flaps (GFs) and microtabs (MTs) are two of the most frequently used passive flow control devices on wind turbines. They are small tabs situated close to the airfoil trailing edge and normal to the surface. A study to find the most favorable dimension and position to improve the aerodynamic performance of an airfoil is presented herein. Firstly, a parametric study of a GF on a S810 airfoil and an MT on a DU91(2)250 airfoil was carried out. To that end, 2D computational fluid dynamic simulations were performed at Re = 106 based on the airfoil chord length and using RANS equations. The GF and MT design parameters resulting from the computational fluid dynamics (CFD) simulations allowed the sizing of these passive flow control devices based on the airfoil’s aerodynamic performance. In both types of flow control devices, the results showed an increase in the lift-to-drag ratio for all angles of attack studied in the current work. Secondly, from the data obtained by means of CFD simulations, a regular function using the proper orthogonal decomposition (POD) was used to build a reduced order method. In both flow control cases (GFs and MTs), the recursive POD method was able to accurately and very quickly reproduce the computational results with very low computational cost.

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